氧化铈稳定的CuO簇在CO,C3H6和NO消除中的催化性能（英文）

研究了CuO与γ-Al2O3和CeO2的相互作用,并由此制备出能有效脱除CO,C3H6和NO的催化剂,考察了不同载体表面CuO簇的分散稳定性和耐老化性能.结果发现,随CuO负载量的增加,CuO簇因与CeO2载体的强相互作用而稳定存在;而在γ-Al2O3表面,CuO簇易聚集成较大的颗粒.另一方面,由于CeO2本身较差的热稳定性,表面分散的CuO在950oC高温处理后烧结.因此,基于γ-Al2O3载体优越的耐老化性能,在γ-Al2O3载体分散CeO2,然后再担载CuO,从而得到了稳定的CuO簇,所得催化剂比CuO/γ-A12O3和CuO/CeO2具有更好的催化性能和抗热老化性能.     

LaMn1—yFeyO3对CH4和CO的催化氧化作用

用程序升温脱附试验考察了LaMn_(1-y)Fe_yO_3型催化剂中B位元素对Co、CH_4氧化活性的影响。发现催化剂的活性与TPD谱上脱氧峰的位置及面积有关,同一催化剂对CO与CH_4的氧化活性中心并不一致。以γ-Al_2O_3为载体制得的锰系ABO_3型催化剂在浸渍微量氧化物助催化剂后,能使CO在130℃完全氧化,CH_4的氧化温度为300～500℃。     

还原态WO_3/Al_2O_3,NiO/Al_2O_3和NiO-WO_3/Al_2O_3催化剂上H_2,CO,O_2的吸附特性

在加氢精制和许多其它催化过程中,Mo,W是主要的活性组分,Co,Ni通常作为助剂,有关Co-Mo体系的研究文献报导很多~[1.2], 但由于钨较难还原和硫化,关于     

活性炭作为载体和还原剂对NO的还原作用

四种国产活性炭既作为载体又作为还原剂被用于ＮＯ还原反应，山楂核炭和山桃核炭作载体时ＮＯ还原转化率很高，椰壳炭和煤质炭作载体时ＮＯ还原转化率则较低，四种活性炭两－两分组现象可由其元素分析，ＮＨ３－ＴＰＤ、还原性及ＮＯ吸附量等结果来解释。另外ＣｕＯ／椰壳炭与ＣｕＯ／煤质炭的ＮＯ还原转化率的差别主要归于二者的ＮＯ吸附量不同，对ＣｕＯ／山楂核炭和ＣｕＯ／山桃核炭，ＮＯ还原转化率随反应温度的相对变化主要由其     

Ni系ABO_3和A_2BO_4型复合氧化物的固态物化性质与NO+CO反应的催化性能

合成了具有钙钛石ＡＢＯ３结构的ＬａＮｉＯ３和Ｌａ０．１Ｓｒ０．９ＮｉＯ３及具有类钙钛石Ａ２ＢＯ４结构的Ｌａ２ＮｉＯ４和ＬａＳｒＮｉＯ４等四个Ｎｉ系复合氧化物催化剂．研究了该系列复合氧化物的晶体结构，缺陷结构，Ｂ位Ｎｉ离子的价态，氧化还原性能及对ＮＯ分子的吸附性能等固态物化性质．考察了它们对ＮＯ＋ＣＯ反应的催化性能，并与ＮＯ直接分解进行了对比研究．探讨了结构因素对Ｎｉ系复合氧化物催化剂的固态物化性质及催化性能的影响．提出了ＮＯ＋ＣＯ反应的反应机理．     

Selective Catalytic Reduction of NO with Propene over Au/Fe2O3/Al2O3 Catalysts

A series of Au/Fe₂O₃/Al₂O₃ catalysts were prepared by the homogeneous deposition-precipitation method. The catalytic activity of the catalyst samples for selective catalytic reduction of NO by propene under oxygen-rich atmosphere was evaluated. The results showed that 2%Au/10%Fe₂O₃/Al₂O₃ exhibited good low-temperature activity. The maximum of NO conversion reached 43% at 300 °C, while it was only 21% over the 2%Au/Al₂O₃ catalyst at the same temperature. The addition of 2% steam to the feed gas had little effect on the catalytic activity. X-ray diffraction results indicated that both Au and Fe₂O₃ particles were highly dispersed over Al₂O₃. H₂-temperature-programmed reduction results indicated that there was strong interaction between Au and Fe₂O₃, which made the reduction of Fe₂O₃ easy. The synergistic effect between Au and Fe₂O₃ was probably responsible for the good catalytic performance of the Au/Fe₂O₃/Al₂O₃ catalyst at low temperature.     

Al2O3-TiO2 SOL-GEL MIXED OXIDES AS SUITABLE SUPPORTS FOR THE REDUCTION OF NO BY CO

Sol–Gel alumina-titania supports were prepared by the co-gelling aluminum tri-sec-butoxide and titanium isopropoxide (10 wt.% TiO₂) at pH 3 and pH 9. Supports showed specific surface areas higher than 250 m²/g, and Lewis acidity was observed by FTIR pyridine adsorption. Cu°, Cu¹⁺ and Cu²⁺species on impregnated Cu/Al₂O₃-TiO₂catalysts were identified by means of FTIR-CO adsorption. A correlation between Cu⁺/Cu²⁺ abundance and the activity for NO reduction by CO is reported.     

WO3改性方法对MnOx/TiO2催化剂低温催化NH3还原NO特性的影响（英文）

采用3种不同的浸渍过程制备了系列WO3改性MnOx/TiO2催化剂,并采用BET比表面积测试、X射线衍射、拉曼光谱、H2程序升温还原、高分辨扫描电镜和原位红外光谱等技术进行表征.结果显示,一步浸渍法和先钨后锰的分布浸渍法制备的催化剂中,Mn和W的协同作用提高了活性组分的分散状态,并阻止了钛载体的转晶;在所有的Mn基催化剂中,Mn物种主要以Mn2O3形式存在,但在15%MnOx-5%WO3/TiO2中出现了少量的MnO2;WO3的加入大大增强了催化剂的还原能力,提高了其表面酸位尤其是B酸的数量与强度,并促进了活性中间物(NH2)的生成.表面Lewis酸在低温SCR反应起主要作用,并且发现NH2也是活性很高的物种.在NH3低温催化还原NO的反应中,一步浸渍法制备的催化剂活性最高.     

Cu/La2O3-ZrO2-Al2O3催化剂的制备及其对NO选择性还原的催化性能

采用将Al(NO3)3、La(NO3)3和ZrOCl2的混合液滴入沉淀剂(NH4)2CO3中的共沉淀法制备La2O3-ZrO2-Al2O3复合载体,然后负载上Cu2+,制成Cu/La2O3-ZrO2-Al2O3催化剂。考察了该催化剂在富氧条件下对C3H6选择还原NO的催化性能,并借助扫描电子显微镜（SEM）、X射线衍射（XRD）、比表面积测定（BET）、吡啶吸附红外光谱（Py-IR）、程序升温还原（TPR）和热重分析（TG）等方法研究催化剂制备方法与结构、性能的关系。实验结果表明,采用将Al(NO3)3滴入(NH4)2CO3制得的γ-Al2O3能有效地增大催化剂的比表面积,加入La2O3能提高催化剂的热稳定性,加入ZrO2能大幅度增加催化剂表面L酸和B酸的酸量。因此,采用共沉淀法制备的La2O3-ZrO2-Al2O3复合载体能够使Cu/La2O3-ZrO2-Al2O3催化剂具有良好的催化性能,最佳催化活性温度为300℃,NO最大转化率高达88.9%,在有10%水蒸气存在的情况下,仍可达81.9%。     

MnOx/ZrO2催化剂表面氧性能

采用ＸＲＤ，ＴＰＤ和ＴＰＲ等技术研究了ＭｎＯｘ／ＺｒＯ２催化剂的表面特性，结果表明，ＺｒＯ２表面的ＭｎＯｘ物种主要以Ｍｎ２Ｏ３和ＭｎＯ２形态存在，经还原－氧化处理后，ＭｎＯｘ物种的分散状况趋好。Ｍｎ－Ｚｒ之间的相互作用促进ＭｎＯ２的分解，而抑制Ｍｎ２Ｏ３的分解。     

PREPARATION OF Ru/Al2O3 CATALYSTS FROM RuCl3

Increasing reduction time increases ruthenium reduction, but even after 6 h, ruthenium is not completely reduced and chlorine is not completely eliminated in Ru/Al₂O₃ prepared from RuCl₃.     

Preferential oxidation of CO in excess H2 over CeO2/CuO catalyst:Effect of calcination temperature

Different from the classical configuration CuO/CeO2 catalyst,the inverse configuration CeO2 /CuO catalyst (atomic ratio of Ce/Cu=10/100) was prepared by impregnation method.Five calcination temperatures were selected to investigate the interaction between CeO2 and CuO support.It is found that as calcination temperature increased from 500 to 900 C,sintering of CeO2 particles on the support occurred together with the diffusion of a portion of Ce 4+ ions into CuO crystals,forming solid solution.Formation of interface complex Ce-O-Cu was suggested by TPR measurements.The catalyst calcined at 700 C gives the highest activity for preferential oxidation of CO in excess H2 stream.     

Investigation of Fe−Ni Mixed‐Oxide Catalysts for the Reduction of NO by CO: Physicochemical Properties and Catalytic Performance

A series of Fe?Ni mixed‐oxide catalysts were synthesized by using the sol–gel method for the reduction of NO by CO. These Fe?Ni mixed‐oxide catalysts exhibited tremendously enhanced catalytic performance compared to monometallic catalysts that were prepared by using the same method. The effects of Fe/Ni molar ratio and calcination temperature on the catalytic activity were examined and the physicochemical properties of the catalysts were characterized by using XRD, Raman spectroscopy, N₂‐adsorption/‐desorption isotherms, temperature‐programmed reduction with hydrogen (H₂‐TPR), temperature‐programmed desorption of nitric oxide (NO‐TPD), and X‐ray photoelectron spectroscopy (XPS). The results indicated that the reduction behavior, surface oxygen species, and surface chemical valence states of iron and nickel in the catalysts were the key factors in the NO elimination. Fe_0.5Ni_0.5O_x that was calcined at 250 °C exhibited excellent catalytic activity of 100 % NO conversion at 130 °C and a lifetime of more than 40 hours. A plausible mechanism for the reduction of NO by CO over the Fe?Ni mixed‐oxide catalysts is proposed, based on XPS and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses.     

MnOx-SnO2 Catalysts Synthesized by a Redox Coprecipitation Method for Selective Catalytic Reduction of NO by NH3

MnO_x-SnO₂ composite oxides prepared by a redox coprecipitation route were tested in selective catalytic reduction of NO by NH₃ at low temperatures. The results showed that the MnO_x-SnO₂ catalyst with a Mn/(Mn+Sn) molar ratio of 75% exhibited the best performance, on which NO conversion of 100% could be achieved at temperatures of 120–200 °C. The characterization results of N₂ adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy indicated that the higher surface area, the formation of solid solution between manganese and tin oxides, and the high oxidation state manganese species were responsible for the high catalytic activity of the MnO_x-SnO₂ catalyst.     

Pt/Al2O3蜂窝状催化剂上NO选择性催化还原反应动力学研究

采用多次涂层和浸渍法制备了蜂窝状Pt/Al2O3催化剂，并在高空速和大气体流量条件下对无梯度循环式反应器和积分反应器上催化剂的活性进行了比较。同时采用循环式反应器对动力学数据进行了测定。根据Langmuir-Hinshelwood模型和实验结果，推测了NO-C3H6-O2体系的SCR反应机理，并导出了NO和C3H6反应速率的数学表达式。据此所计算的理论模拟值能够与实验值很好地吻合。实验结果表明，氧气浓度对NO和C3H6的反应速率有明显的影响，二者均随着氧浓度c (O2)的增加达到峰值，再增加氧气浓度时，C3H6的反应速率r(C3H6)保持不变，而NO反应速率r (NO)却下降，而且下降的程度随着温度的升高而加剧。同时，随着氧气浓度增加，r (NO)达到最大值时的温度亦随之下降。     

NH4β分子筛上NO的低温催化还原

以离子交换法制备的NH4β分子筛为催化剂,考察在无氨、有氨及SO2存在等不同条件下NO低温选择催化还原性能,并通过程序升温分解反应研究NH+4消耗引起的催化剂失活,NH3程序升温脱附(NH3-TPD)研究催化剂的再生性能,为开发无氨或气相间隙喷氨脱除NOx的新过程奠定基础.     

Solid Solutions of WO3into Zirconia in WO3-ZrO2 Catalysts

Catalysts in the WO₃-ZrO₂ system were produced by coprecipitation of aqueous solutions of zirconium oxynitrate and ammonium metatungstate. Samples were characterized by X-ray powder diffraction, thermogravimetry, and refinement of their crystalline structures with the Rietveld method. This coprecipitation gave rise to solid solutions of tungsten oxide into zirconia; the initial phase was amorphous and crystallized into two tetragonal crystalline phases, T1 and T2, when samples were annealed at 560°C. The main difference between both phases was the oxygen position along the c axis. In the phase with higher symmetry, T2, an oxygen atom was at one-half of the unit cell, 0.50(2), producing flat crystallite surfaces perpendicular to the c axis, while in the phase with the lower symmetry, T1, it was at 0.447(2), and gave rise to rough crystallite surfaces parallel to (100) planes. The interpenetrating tetrahedra forming the representative polyhedron of the crystalline structure were almost nondeformed in the phase with higher symmetry, because all Zr-O atom bond lengths were very similar. As the annealing temperature of the sample was increased, the dissolved tungsten atoms in the phase with higher symmetry segregated to the crystallite's surface.     

氢部分选择性催化还原NO反应研究

在低钯含量活性非均布Pd/Al2O3催化剂上，实现了富氧条件下，氢部分选择性催化还原NO过程，低温、富氧条件下NO的转化率高达80％－100％。NO直接分解实验表明，600℃，NO分解转化率在无氧时为17．3％，有0．5％氧存在时接近于0。氢非选择性还原NO条件下，100℃以下，NO转化率为100％。根据实验结果及文献，推测了氢部分选择性还原NO过程中可能存在的反应，不同的反应温度下，NO脱除反应有所不同。在115℃以下，NO还原产物为NH3；115℃－155℃，NO还原产物为NH3、N2O和N2；155℃以上，NO还原产物中无NH3存在。NO还原反应与氢氧反应是平行的竞争反应。     

Rh/Al2O3上CO和NO的吸附性能及相互作用

利用ＴＰ－ＩＲ动态方法研究了ＣＯ和ＮＯ在Ｒｈ／Ａｌ２Ｏ３上吸附性能和相互作用的动态行为，结果表明，Ｒｈ／Ａｌ２Ｏ３的孪生中心对ＣＯ的吸附强于对ＮＯ的吸会，线式和桥式中心则对ＮＯ的吸附强于对ＣＯ的吸附，ＣＯ和ＮＯ共吸附－ＴＰ（ＣＯ和ＮＯ中）－ＩＲ动态过程结果揭示出２２２４ｃｍ＾－１谱带的出现和强度的增加与孪生ＣＯ谱带以及吸附的ＮＯ谱带的强度减弱同时发生，表明是由吸附的ＮＯ和孪生ＣＯ形成Ｒｈ－ＮＣＯ。     

用穆斯堡尔谱研究镧改性铁催化剂的表面氧化性能

用穆斯堡尔谱研究镧改性铁催化剂的表面氧化性能周钰明（东南大学化学化工系，南京２１００９６）张爱民，丁莹如（南京大学化学系，南京２１００９３）关键词氧化镧改性，氧化作用，氧化铁催化剂，氢，一氧化碳在催化反应中，反应物分子首先吸附到催化剂表面，催化剂活性...